2nd set issues

So I've noticed over the last couple of years that I really struggle (mentally not physically) during the 2nd set. My last couple of matches really reinforced this notion. I'll go up 6-0,6-1 in the first set and then something happens in the second set where I really struggle. I start making stupid mistakes, double faulting etc. I've tried really hard to forget about the first set and try and play the second set as if it was the first. Also try and completely forget about the score and just play each game/point as if the score was 0,0. I don't think I'm getting overly confident/cocky just think its more of an issue where I mentally go to sleep/get bored and all of sudden find myself in a real battle. Though I don't have any recent matches to recall from, I don't think I have this issue when the first set is much closer or if I lose the first set. I'm a solid 3.5/4.0 player who doesn't lose very often.

Anybody else have this issue? Any mental tricks you use to try and fix it?

...sometimes it might be because your opponent has geared-up their game after they lose the first set by making necessary adjustments, finding their groove, etc....and that might account for why the 2nd sets can be closer (in combination with you relaxing a little after the 1st).

You say you're winning 1st sets by scores like 6-0 or 6-1, and you mention you don't lose very often. ...so the bigger question is whether you should be playing at a higher level against better competition...that might be the best way to train your mind Re: focus/concentration...because you'll be in more of a dog-fight throughout course of an entire match

I have the same exact problem as you. I usually come out very fast and strong in the first set then i honestly have no idea what happens in the second. i play differently. i have come to this conclusion...
1. dont over think your strokes.
2. what you did in the first set worked..so stick to the game plan. over thinking things about the match such as mechanics, how your opponent is playing, the score, can really affect your game.
3. The more you think about these things the harder you try to pull yourself out of it. and that often leads to being tense and not performing to the best of your ability.
4. just stay focused. do what you did in the first set and dont over analyze anything.
5. you said you have tried to forget about the first set completely and move on to the second...DONT! Remember what worked in the 1st set and come right back out in the 2nd and do more of the same. dont let up. dont tense up. dont hold back. be steady, and dig deep if it starts to get close.

Brad Gilbert talks about this in Winning Ugly. Sometimes the winner of the 1st set becomes the "Happy Camper" and the loser becomes the "Wounded Bear". The opponent who loses the 1st set is now back up against a wall forced to win the next set to stay in the match and will fight like mad to win the set. You on the other hand can lose that set and still win the match. So "the Bear" comes out very intense in the 2nd set while you "the Camper" may be a little too relaxed knowing that you have an insurance set left in your pocket.

Great answers, and I think I can take a piece of each one and give it a try.

1- I'm playing 3.5 this year but will for sure be playing 4.0 next regardless of my ranking. I was expecting to get moved up (by the ranking system) last year but it didn't happen. Probably because I give up enough games (mostly during the 2nd set). But I agree. If I'm battling out the first set I'll at least be mentally prepared for a 2nd set battle as well.

2-Remember what was working for me in the first set. Great advice, seriously and I will work on that.

3- Lose interest/Get bored. Exactly what I was thinking as well. Maybe playing up a level next year will hopefully take care of that issue.

4- I need to start thinking ahead a little bit more about my mental state as well as my opponents if I walk all over him in the first set. Can't think I'm going to be playing the same player in the 2nd set as I was in the first. I seriously hate getting to a 3rd set tie break and really need to play that second set as if it were my last.